Activity investigation of imidazolium-based ionic liquid as catalyst for friedel-crafts alkylation of aromatic compounds

Article abstract of DOI:10.14233/ajchem.2015.17407

N-Methylimidazolium ionic liquids were synthesised from N-methylimidazole and 1-bromobutane by two-step method. The alkylation of benzene and other aromatic compounds through improved Friedel-Crafts reaction was investigated in these ionic liquids. The imidazolium-based ionic liquids showed both high activity and high selectivity for this reaction. In particular, remarkable enhancement of the catalytic effect of the imidazolium-based ionic liquids was observed for the ionic liquids containing the PF₆^- anion. The effects of various types of anions, ionic liquid dosage, reaction temperature and molar ratio of aromatic compound to 1-bromobutane/tertbutyl alcohol were explored using [Bmim]PF₆ or its mixture with AlCl₃ as catalyst. The synthesis yielded improved results over those obtained using either neat AlCl₃ or other imidazolium-based ionic liquids as catalyst. The ionic liquids can also be recycled and reused in contrast to traditional solvent-catalyst systems.

Full text of DOI:10.14233/ajchem.2015.17407

Asian Journal of Chemistry; Vol. 27, No. 2 (2015), 649-653
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2015.17407
Activity Investigation of Imidazolium-Based Ionic Liquid as
Catalyst for Friedel-Crafts Alkylation of Aromatic Compounds
*
MINGJIAN CAI and XIUGE WANG
Department of Chemistry, Tangshan Normal University, Tangshan 063000, Hebei Province, P.R. China
*Corresponding author: Fax: +86 315 3863122; Tel: +86 315 3863393; E-mail: cmj_1237@aliyun.com
Received: 17 February 2014;
Accepted: 7 May 2014;
Published online: 10 January 2015;
AJC-16639
N-Methylimidazolium ionic liquids were synthesised from N-methylimidazole and 1-bromobutane by two-step method. The alkylation
of benzene and other aromatic compounds through improved Friedel-Crafts reaction was investigated in these ionic liquids. The imidazolium-
based ionic liquids showed both high activity and high selectivity for this reaction. In particular, remarkable enhancement of the catalytic
effect of the imidazolium-based ionic liquids was observed for the ionic liquids containing the PF6- anion. The effects of various types of
anions, ionic liquid dosage, reaction temperature and molar ratio of aromatic compound to 1-bromobutane/tertbutyl alcohol were explored
using [Bmim]PF6 or its mixture with AlCl3 as catalyst. The synthesis yielded improved results over those obtained using either neat AlCl3
or other imidazolium-based ionic liquids as catalyst. The ionic liquids can also be recycled and reused in contrast to traditional solvent-
catalyst systems.
Keywords: Imidazolium-based ionic liquids, Alkylation, Friedel-Crafts, Aluminium chloride.
Recently, ionic liquids (ILs) have been extensively applied
as catalyst or reagent in organic and refinery chemistry because
of their unique properties, such as negligible vapour pressure,
good solvating ability, potential recoverability and recyclability
INTRODUCTION
Friedel and Crafts discovered the reaction of benzene with
alkyl halides in the presence of aluminium chloride in 1877.
Since then, Friedel-Crafts alkylation of aromatic compounds
catalyzed by Lewis acids, such as BF3, ZnCl2, TiCl4 and SbF5,
using various alkylating reagents, such as alkyl halides and
alkenes, have been used both in the laboratory and in the
petroleum industry1,2.
and tuneable acid types (Lewis or Brønsted) and strength12-14
.
However, before these liquids can be used commercially on
an industrial scale, the process variables need to be optimized
in the laboratory, not only in batch and continuous reactor
systems for maximum reactant conversion, but also the product
yield and catalyst selective ability.
Current commercial alkylation processes are catalyzed
primarily by concentrated sulfuric acid or hydrofluoric acid.
The sulfuric acid process produces large amounts of spent acid
and acid-soluble oils, which are costly to regenerate. Anhy-
drous HF is highly toxic and its leakage produces dangerously
stable aerosols at the ground level. In addition, equipment
corrosion, transport, hazard management and environmental
liability associated with the disposal of spent acids are
disadvantageous for both processes. Hence, alternative
processes that are relatively safe are continuously developed3.
Great effort has been focused on improving this process using
environmentally safer catalysts, such as H-ZSM-5, H-ZSM-
12, HY, lays4,5, cation-exchange resin6, mesoporous materials7,
zeolites8,9 and molecular sieves10. However, these catalysts
often have certain disadvantages, such as rapid deactivation
due to the fouling of pores, which results in low product yield,
loss of reaction selectivity11 and lack of recyclability.
In the viewpoint of its application, this study reports the
alkylation of several aromatic compounds including benzene,
phenol, toluene, thiophene, anisole and acetanilide with alkyl
halide and alcohol in the presence of dialkylimidazolium-based
ionic liquids, such as 1-butyl-3-methylimidazolium bromide
([Bmim]Br), 1-butyl-3-methylimidazolium chloride ([Bmim]Cl),
1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6),
1-butyl-3-methylimidazolium tetrafluorobarate ([Bmim]BF4)
and 1-butyl-3-methylimidazolium hydrogensulfate ([Bmim]HSO4)
(Fig. 1). For comparison, AlCl3 was also used to catalyze the
reaction.
EXPERIMENTAL
The experiments were conducted using analytical grade
solvent and chemicals without further purification. The com-
ponent and distribution of the products were verified by gas

650 Cai et al.
Asian J. Chem.
of the aromatic compound:bromoethane (or t-butyl alcohol):
ionic liquid is shown in every table. At the end of the reaction,
the organic layer was easily decanted from the catalyst-ionic
liquid system and any organic residues were removed by
extraction with diethylether. When the catalyst containingAlCl3
was used, the reactive mixtures were handled as follows. The
mixture was added to an excess of crushed ice and 3 M HCl.
The organic phase was separated, the extract was added to
wash (solvent) the acid layer, the combined extracts were
washed three times with water and the solvent was removed
by rotary evaporator. For nitromethane, the organic layer was
washed with 3M NaOH. The viscous residue was dissolved in
benzene and passed through a short column of silica gel to
remove any polymeric materials.
N
N
N
N
N
N
PF6
Br
Cl
c
b
a
N
N
N
N
HSO4
BF4
e
d
e
[Bmim]HSO4
[Bmim]BF
d
[Bmim]PF6
c
[Bmim]Cl
b
[Bmim]Br
a
4
Fig. 1. Structures of the alkylimidazolium-based ionic liquids used in this
investigation
chromatography/mass spectrometry [GC (Agilent 6890)/MS
(Hewlett-Packard 5973)]. The infrared (IR) spectrometer used
to analyse the catalyst was supplied by Brucher Co., Germany.
Synthesis of ionic liquid: [Bmim]Cl and [Bmim]Br were
prepared using the following procedure. Toluene, N-methyl-
imidazolium and 1-chlorobutane or 1-bromobutane were
placed into a dry round-bottomed flask equipped with a reflux
cooler, a magnetic agitator and a glass thermometer. The
mixture was heated under agitation and the temperature was
maintained between 80 and 85 °C. After 24 h of reaction, the
mixture was cooled to room temperature. After freezing in a
refrigerator, toluene and the unreacted reactants were decanted.
The product was then washed using acetonitrile as solvent.
The washed product was dried in a vacuum drying box to
remove residual solvent and water.
The reactive product was then analysed quantitatively by
GC. The contents of the major product were determined using
the normalization method. The product yields are presented
in the tables. The synthesized mono and dialkylation products
were directly isolated from the reaction mixture and positively
identified through their IR and mass spectra and elemental
analysis.
Inlet and detector temperatures were set constant to
300 °C. The aromatic compounds were used as internal
standard to calculate the reaction conversions or yield. GC-
MS analyses were performed using a Hewlett Packard GC-
MS 5973 with RTX-5MS column (length = 30 m, inner
diameter = 0.25 mm and film thickness = 0.5 µm). The
temperature for the GC-MS analysis heated samples was
programmed from 60 to 280 °C at 10 °C/min and then held at
280 °C for 2 min. The inlet tempe-rature was set constant to
280 °C. MS spectra were compared with the spectra obtained
in the NIST library.
[Bmim]PF6, [Bmim]BF4 and [Bmim]HSO4 were prepared
from the anion exchange of [Bmim]Cl with sodium hexafluoro
phosphate, ammonium tetrafluoroborate, sodium sulfate and
sulfuric acid, respectively, according to the modified procedure
described in the literature15-17
.
General alkylation procedure: The utility of dialkylimi-
dazolium-based ionic liquids were investigated in the
alkylation of aromatic compounds with bromoethane(t-butyl
alcohol) (Scheme-I). The specified amount of catalyst and
other reactants were added together, i.e., the catalyst and
alkylating reagent were allowed to react prior to the addition
of the substrate. A solution of aromatic compounds in the
chosen solvent was added dropwise for over 5 min to a stirred
mixture of alkylating reagent and ionic liquid (orAlCl3) in the
same solvent at 25 °C. Stirring was continued at the specified
temperature and time described in the tables. The molar ratio
RESULTS AND DISCUSSION
Reactive sites in electrophilic substitution are generally
affected by the original substituent. In our work, investigations
on the Friedel-Crafts alkylation of the non-substituted and
mono-substituted aromatic compounds with ortho- and para-
directing groups as reactive substrate was conducted as initial
efforts for preparing the mono and disubstituted compounds
in good conversion by direct electrophilic substitution reaction.
Influences of various of catalysts on the reaction
results: Reactions were studied using aromatic compounds
and bromoehane (t-butyl alcohol) in ionic liquid under specific
conditions (Scheme-I). Table-1 shows the effect of the ionic
liquid catalysts on the alkylation reaction. ionic liquids, such
as [Bmim]PF6, [Bmim]BF4 and [Bmim]HSO4 exhibited greater
activity than the other two ionic liquids studied in this work
(Table-1, Entries 8-10, 13-15 and 18-20). In particular,
[Bmim]PF6 (Table-1, Entries 8, 13, 18) exhibited excellent
performance in the alkylation of aromatic compounds.
Moreover, the same cation and different anions of the ionic
liquids have significant effects on the alkylation of aromatic
compounds. Generally, Lewis acid strength has a vital role in
the catalysis of electrophilic aromatic substitution. Anions with
high basicity (e.g., acetate) enable proton transfer in
imidazolium-based ionic liquids, providing an imidazole-2-
ylidene derivative (N-heterocyclic carbene) and an acid (e.g.,
R
R
R
Cat
CH2CH3
CH3CH2 Br
Temp
CH2CH3
1g
H
H
R=
R=
R=
R=
H
1f
R=
1
R=
R=
2g
3g
4g
NHCOCH3
OH
NHCOCH3
OH
NHCOCH3
2f R=
2
3
4
3f
4f
R=
R=
OH
R=
R=
OCH3
OCH3
OCH3
CH3
CH3
CH3
Cat
C(CH3)3
(CH3)3COH
Temp
C(CH3)3
5
5f
5g
Cat
CH3CH2 Br
CH2CH3
Temp
S
S
6
6f
Scheme-I:Alkylation of the aromatic compounds with bromoethane (t-butyl
alcohol)

Vol. 27, No. 2 (2015)
Activity Investigation of Imidazolium-Based Ionic Liquid as Catalyst for Friedel-Crafts Alkylation 651
Bu
TABLE-1
Bu
O
N
N
ALKYLATION OF AROMATIC COMPOUNDS WITH
BROMOETHANE (t-BUTYL ALCOHOL) USING
DIFFERENT TYPES OF CATALYST
N
N
O
£º
HO
O
Conversion of
aromatic
compound (%)
Aromatic Bromoethane/
compound t-butyl alcohol
Me
Me
Entry
Catalyst
Scheme-II: Possible acid-base equilibrium between the constitutive ions of
a 1,3-dialkylimidazolium ionic liquid
1
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
4
4
4
4
4
5
5
5
5
5
6
6
6
6
6
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
(CH3)3COH
(CH3)3COH
(CH3)3COH
(CH3)3COH
(CH3)3COH
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
a
b
c
d
e
a
b
c
d
e
a
b
c
d
e
a
b
c
d
e
a
b
c
d
e
a
b
c
d
e
22.5
24.5
30.2
31.3
29.7
75.6
79.2
97.5
83.3
80.4
73.2
74.5
98.8
83.1
81.2
25.4
31.3
94.8
80.0
65.8
22.9
34.7
35.8
37.2
40.4
24.7
29.7
35.3
32.6
36.8
2
4-5, 10 and 15-16), whereas weak catalytic activity was
observed for the alkylation of the ionic liquid alone (Table-1,
Entries 1-5, 21-30). Moreover, the performance of the mixed
catalyst was better than that of neat aluminium chloride.
However, exceptions were also noted (Table-2, Entries 8, 11-
12 and 17). The catalytic activity of the mixed catalyst conta-
ining [Bmim]PF6 was superior to that of any other combined
catalysts. However, some factors causing the deactivation of
ionic liquid and aluminium chloride were found. For instance,
the moisture-sensitivity of [Bmim]AlCl4 ionic liquid and the
dissolving elution of [Bmim]AlCl4 owing to both benzene and
trace water in materials may be the main causes for the catalyst
deactivation19. In addition, the deactivation of ionic liquids
could also attributed to the decrease of the Lewis acidic strength
and density resulting from the loss of the highly Lewis acidic
species Al2Cl6Br-20.
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
TABLE-2
ALKYLATION OF AROMATIC COMPOUNDS WITH
BROMOETHANE (t-BUTYL ALCOHOL)
USING MIXED CATALYSTS
Bromoethane
(tert-butyl
alcohol)
Conversion of
aromatic
compound (%)
Aromatic
compound
Entry
Catalyst
1
2
1
1
1
1
1
1
5
5
5
5
5
5
6
6
6
6
6
6
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
(CH3)3COH
(CH3)3COH
(CH3)3COH
(CH3)3COH
(CH3)3COH
(CH3)3COH
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
CH3CH2Br
AlCl3
60.8
64.2
72.8
92.3
86.2
72.2
75.1
74.2
75.2
90.3
55.6
71.8
63.9
65.1
77.4
80.3
56.6
73.9
a-AlCl3
b-AlCl3
c-AlCl3
d-AlCl3
e-AlCl3
AlCl3
Reaction conditions: molar ratio aromatic compound/bromoethane
(t-butyl alcohol)= 1:1.1; Wcat = 15 %; T = Reflux temp; t = 2 h
3
4
5
acetic acid), as shown in Scheme-II18. This finding probably
indicates that the anion strongly interacts with the proton on
the 2-position of the imidazolium ring. [Bmim]PF6 also exhibits
greater acidity than the other ionic liquids, such as [Bmim]BF4,
[Bmim]Br and even [Bmim]HSO4. The possible reason for
the high reactivity of [Bmim]PF6 for this reaction is that
[Bmim]PF6 is equal to the Lewis acidic ionic liquid and may
reduce the formation of a nucleophilic carbene catalyst in the
alkylation, as displayed in Scheme-II. Nucleophilic carbene
may hinder the production of alkanium ion, which is the
reactive intermediate according to the mechanism of Friedel-
Crafts alkylation reaction. The results showed that [Bmim]PF6
is an excellent catalyst and solvent for the alkylation of
aromatic compounds.
6
7
8
a-AlCl3
b-AlCl3
c-AlCl3
d-AlCl3
e-AlCl3
AlCl3
9
10
11
12
13
14
15
16
17
18
a-AlCl3
b-AlCl3
c-AlCl3
d-AlCl3
e-AlCl3
Reaction conditions: molar ratio aromatic compound/bromoethane
(t-butyl alcohol) = 1:1.1; Wcat = 15 %; T = Reflux temp; t = 2 h
To obtain more information on the reaction performances
of ionic liquids as catalyst and reagent, a mixed catalyst of
ionic liquid and aluminium chloride was investigated.
The molar ratio of aromatic compounds to bromoethane
(t-butyl alcohol) with 1:1.1 constant was maintained and the
catalyst with 15 % mass of reactants was added. The results
are summarised in Table-2, which shows that better results
were obtained with the mixed catalyst of ionic liquid and
aluminium chloride. Notably, good result was achieved with
the ionic liquid containing aluminium chloride (Table-2, Entries
Influences of the dosage of catalysts on the reaction
results: [Bmim]PF6, which was effective for alkylation when
used alone (Fig. 2, benzene, toluene, thiophene) but not when
mixed with AlCl3, was selected as specified catalyst to inves-
tigate the effect of its dosage on the results. Obviously, the
yield increased with increasing ionic liquid. Fig. 3 shows the
result of experimental investigations of [Bmim]PF6 withAlCl3
were used to catalyse the aromatic compound alkylation with
alkylhalide(alcohol) under specified conditions. The high
activation began almost from the start of the addition of the

652 Cai et al.
Asian J. Chem.
appointed product decreased when [Bmim]PF6 exceeded 30 %
of the total mass of the catalyst. Considering all these factors,
20 to 30 % W([Bmim]PF6) is appropriate.
60
50
40
30
Influence of catalyst on product selectivity: The results
of the alkylation of aromatic compounds with bromoethane-
(t-butyl alcohol) in different catalyst-ionic liquid systems are
shown in Table-3. Scheme-I shows that 'o-' and 'p-' position
isomer products (Scheme-I, 2-5 f, 2-5 g) were obtained in the
alkylation. We would expect 'p-' substituted aromatic comp-
ounds because of steric hindrance to be the major product. As
a matter of fact, it fell out as we expected, 'p-' isomer is the
major product when we adopted [Bmim]PF6 or its mixture
with AlCl3 as catalyst. In addition to steric hindrance, other
reasons that lead to the phenomenon may exist, which is the
subject of our next investigation.
1f and 1g
5f and 5g
6f
20
10
20
30
40
50
60
70
80
90
100
Content of [Bmim]PF6 (%)
Influence of reaction temperature on alkylation: Reac-
tion temperature has an important effect on reaction dynamics
and thermodynamics. Therefore, the effect of reaction tempe-
rature on the results of the alkylation catalysed by [Bmim]PF6-
AlCl3 (W([Bmim]PF6 = 50 %) or [Bmim]PF6 was investigated
in detail (Fig. 4). The influence of reaction temperature on the
conversion is shown in Fig. 4. A remarkable effect on alkylated
conversion was observed. Increasing the reaction temperature
accelerated the molecular thermal agitation and the molecular
collision probability between the carbonium ion and aromatic
ring. Therefore, the alkylation was accelerated, 82.5 % (toluene)
and 93.3 % (phenol) with high conversion for aromatic
compound at 40 to 60 °C was achieved. If the reaction
Fig. 2. Overall effect of catalyst loading; Reaction conditions: molar ratio
aromatic compound/bromoethane (t-butyl alcohol) = 1:1.1; T =
Reflux temp; t = 2 h
90
75
60
45
1f and 1g
5f and 5g
6f
30
2f and 2g
3f and 3g
4f and 4g
90
75
60
15
0
5
10
15
20
25
30
35
40
45
50
Content of ionic liquid in mixed catalysts (%)
Fig. 3. Results of the alkylation of aromatic compounds with bromoethane (t-
butyl alcohol) under different kinds and dosages of catalysts; Reaction
conditions: molar ratio aromatic compound/ bromoethane (t-butyl
alcohol) = 1:1.1; T = Reflux temp; t = 2 h; Wmixed catalyst = 10 %
45
1f and 1g
5f and 5g
30
15
6f
catalyst. The conversion increased with increasing catalyst
amount. When the ionic liquid (AlCl3) content reached 20 to
30 %, the conversion reached its maximum [96 % (phenol,
wt. %) and 68.8 % (thiophene, wt. %)].Afterward, the conver-
sion remained unchanged or decreased with increasing catalyst
content. This phenomenon may be due to the fact that the
concentration of carbonium ion increases with increase in
catalyst, which can accelerate the reaction and increase the
conversion of the aromatic compound. However, a series of
side reactions also occurred simultaneously and the yield of
2f and 2g
3f and 3g
4f and 4g
20 25 30
35 40 45 50 55 60 65 70 75
Temperature (°C)
Fig. 4. Effect of reaction temperature on the results of the alkylation of
aromatic compounds with bromoethane (t-butyl alcohol); Reaction
conditions: molar ratio aromatic compound/bromoethane (t-butyl
alcohol) = 1:1.1; Wcat = 25 %; W ([Bmim]PF6) =50 %; t = 2 h. Note
that the temperature is the temperature of the heater
TABLE 3
FRIEDEL-CRAFTS ALKYLATION OF AROMATIC COMPOUNDS WITH BROMOETHANE (t-BUTYL ALCOHOL)
Entry
Reactant
Catalyst
[Bmim]PF6 + AlCl3
[Bmim]PF6
Major productb yield (%)
Selectivity to major product (%)c
1
2
3
4
Toluene + t-butyl alcohol
Acetanilide + chloroethane
Phenol + chloroethane
Anisole + chloroethane
55.3
56.5
67.8
54.8
90.5
92.3
91.2
88.1
[Bmim]PF6
[Bmim]PF6
Reaction conditions: molar ratio aromatic compound/bromoethane(t-butyl alcohol)= 1:1.1; Wcat = 15 %; T = Reflux temp; t = 2 h. b. Major product
is ‘p-’ isomer; c. Molar ratio of ‘p-’ to ‘o-’isomer

Vol. 27, No. 2 (2015)
Activity Investigation of Imidazolium-Based Ionic Liquid as Catalyst for Friedel-Crafts Alkylation 653
temperature is further raised, the conversion of aromatic
compound would inevitably decrease. From the viewpoint of
conversion and energy consumption, 40 to 60 °C is the optimal
reaction temperature for the alkylation of aromatic compounds.
Influences of molar ratio of aromatic compound and
bromoethane (t-butyl alcohol) on the alkylation: The influence
of the molar ratio of aromatic compound and bromoethane
(t-butyl alcohol) on the conversion of the alkylation using
[Bmim]PF6 ionic liquid is shown in Fig. 5. The alkylation
results show that as n(bromoethane/t-butyl alcohol) increased,
the conversion of the aromatic compound increased until the
maximum was reached and then declined. The maximum of
88.1 % (benzene), 65.6 % (toluene), 73.5 % (thiophene), 69.6 %
(acetanilide), 93.2 % (phenol) and 73.4 % (anisole) in conver-
sion were observed when n(bromoethane/tert-butanol) were
3, 3, 3.5, 2, 2 and 2, respectively. At higher n(bromoethane/
tert-butanol) value, the concentration of active carbonium ion
would be diluted and the alkylation would be weakened,
resulting in a lower conversion. However, with an increase in
n(bromoethane/tert-butanol), the cubic capacity effect
decreases; thus, the circulation amounts increased to a great
extent, consequently resulting in higher production cost21.
Conclusion
The alkylation of aromatic compounds with bromoehane/
tert-butyl alcohol was carried out in a series of imidazolium
ionic liquids or its mixtures with AlCl3. The results showed
that [Bmim]PF6 ionic liquids are the most suitable media for
the Friedel-Crafts alkylation of aromatic compounds. The
reactions proceeded at an improved rate at relatively lower
temperature, yielding high product conversion. [Bmim]PF6 was
found to be the better solvent-catalyst system than the AlCl3
system, which can efficiently substitute the AlCl3 catalysis
system. High conversion of the limiting reactant could be
obtained using this catalyst. Moreover, the selectivity of the
target product exhibited a large increase. The effects of various
parameters, such as temperature, catalyst type and catalyst
loading, on the aromatic compound conversion and product
selectivity were studied. The applications of imidazolium-
based ionic liquids as solvents or catalyst for other reactions
are under investigation in our laboratory.
ACKNOWLEDGEMENTS
The authors are grateful to Tangshan Normal University
and Fund of Science Foundation of Tangshan Normal Univer-
sity (No. 2014D02) for financial support.
90
75
60
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